Research On Transmission Scheme And Resource Allocation For The Next Wireless Communication Systems

Current MIMO spatial diversity techniques, especially the spatial transmit diversity techniques. For the maximum ratio transmitting (MRT), which the transmitter knows the CSI(Channel State Information), we then propose a new transmit diversity scheme, namely optimal-selection maximum ratio transmit (the OMRT scheme), to meet the system performance and reduce the hardware complexity, power consume further. Based on the theory about random matrix and order statistics, we carry out a though analysis for the OMRT. The closed-form outage probability and the BER (Bit Error Rate) of the OMRT system, for Rayleigh fading scenario, are presented. The analytical results are verified by simulation.Second, because the conventional MIMO systems require the number of radio frequency circuits should be equal to the number of antennas. Obviously, that will lead the system hardware complexity, cost and power consumption increase deeply, especially for the mobile receiver. So with the transmitter and the receiver joint design, two new MIMO schemes are proposed to improve the system performance and reduce the hardware complexity, cost and so on. We investigate a downlink MIMO scheme combining maximum ratio transmission and receiver antenna selection combining, in which a single receive antenna, maximizing the receive SNR, is selected for demodulation. We refer to it as the MRT/RAS scheme. Then we investigate another MIMO scheme, in which base station selects a transmit antenna with the largest SNR and mobile set adopts the MMRC (Minimum-Selection Maximum Ratio Combining) technology, namely the TAS/MMRC scheme. The analysis and simulation demonstrate that the MRT/RAS scheme can achieve array gain and full diversity order gain, as if all the receive antennas were used. It is shown that the MRT/RAS scheme outperforms some more complex space-time codes of the same spectral efficiency. We also carry out a though analysis for the TAS/MMRC. Extensive analysis and simulation results are presented to validate the analysis and shown that the two schemes are suitable for the downlink communications in cellular radio systems and provide theory guidance for their practical applications.Moreover, we study the adaptive resource allocation for the multiuser MIMO-OFDM system based on eigen-beamforming. First, only considering the users'BER requirements, we propose an adaptive resource allocation criteria to minimize the total system transmit power.We quantitatively analyze the system performance, including the obtained multiuser diversity gain. Then we propose a hypo-optimal resource allocation algorithm while ensuring the fulfillment of users'QoS requirements and considering the scheme's practicability and computational complexity. Furthermore, we study the adaptive resource allocation for the correlated MIMO-OFDM systems via a new channel model, called virtual channel representation, which consider not only scatterers close to transmitters and receivers, but also the scatterers between transmitters and receivers.Last, we have a research on the resource allocation rules in order to maximize the multiuser MIMO-OFDM system's instantaneous capacity under different SNR, including the practical V-BLAST/OFDM system. In addition, we address a simple iterate resource allocation to maximize the system capacity and consider the users'QoS requirements at the same time. In order to improve the spectral efficiency under low SNR, we joint the power reallocation algorithm with the adaptive resource allocation in the end.